Pure Cobalt is a hard, lustrous, silver-gray transition metal known for its exceptional high-temperature strength, magnetic properties, and outstanding resistance to wear and corrosion. It exists in both HCP and FCC crystal structures, giving cobalt excellent mechanical stability across wide temperature ranges.
Definition & Commercial Grades
| Grade | Typical Purity |
|---|---|
| Commercially Pure Cobalt | 99.3 – 99.8% Co |
| High-Purity Cobalt | ≥ 99.95% Co |
Chemical Composition (Typical)
| Element | Content (%) |
|---|---|
| Cobalt (Co) | ≥ 99.5 |
| Iron (Fe) | ≤ 0.25 |
| Nickel (Ni) | ≤ 0.20 |
| Carbon (C) | ≤ 0.02 |
| Silicon (Si) | ≤ 0.02 |
| Sulfur (S) | ≤ 0.01 |
| Oxygen / Nitrogen | Trace |
Key Mechanical Properties
| Property | Typical Value |
|---|---|
| Tensile Strength | 345 – 620 MPa |
| Yield Strength (0.2%) | 200 – 350 MPa |
| Elongation | 20 – 40% |
| Hardness | ~85 – 100 HRB |
| Fatigue Resistance | Good |
| Wear Resistance | Very good |
Physical Properties
| Property | Value |
|---|---|
| Density | 8.90 g/cm³ |
| Melting Point | 1495 °C |
| Elastic Modulus | ~210 GPa |
| Thermal Conductivity | ~70 W/m·K |
| Thermal Expansion | ~13.0 µm/m·K |
| Magnetic Behavior | Ferromagnetic |
| Curie Temperature | 1121 °C |
Strengthening & Metallurgical Behavior
• HCP structure at room temperature
• Transforms to FCC above ~417 °C
• Strengthened by cold working and grain refinement
• Excellent strength retention at elevated temperatures
• Stable under thermal cycling with no brittle intermetallics
Corrosion & Environmental Resistance
Pure cobalt offers excellent resistance to oxidation, hot corrosion, acids, alkalis, and molten salt environments. It outperforms pure nickel and many stainless steels at high temperatures.
Available Forms
Ingots
Bars & rods
Sheets & plates
Foils
Wire
Powders, pellets & granules
Applications
Aerospace
High-temperature structural parts
Turbine engine components
Medical
Orthopedic implant systems
Surgical tools
Magnetic & Energy
Permanent magnets
Battery materials and catalysts
Industrial
Hardfacing materials
Cutting tools
Valve seats
Advantages
✔ Exceptional high-temperature strength
✔ Outstanding wear and corrosion resistance
✔ Strong magnetic behavior
✔ Good ductility vs refractory metals
✔ Stable under thermal shock
Limitations
❌ High cost and supply volatility
❌ Difficult machining
❌ Health & safety precautions required
❌ Often alloyed rather than used structurally
Why Choose Pure Cobalt?
Choose pure cobalt when extreme temperature stability, wear resistance, magnetic performance, and chemical durability are required without alloying.
Pure cobalt bridges the gap between structural metals and superalloys, enabling extreme-environment applications where conventional metals fail.